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IRISH-RACER-14
03-07-2011, 09:49 AM
i bought a bike. the cylinder was damaged. i sent the cylinder away to be replated or whatever its called. i got the bike with the cylinder off. im just wondering is there anyway of me knowing if the bottom end is ok?
also the bike is an 01 yz125
sly400ex
03-07-2011, 12:03 PM
Best advice, let someone look at it that knows what they are doing.:)
IRISH-RACER-14
03-07-2011, 12:10 PM
Originally posted by sly400ex
Best advice, let someone look at it that knows what they are doing.:)

i would but. the only people in the area will tell me there is a problem when there is not and they will charge me double..
ZeroLogic
03-07-2011, 01:20 PM
It don't really hurt to just replace the crank and rod and isn't to much. 200 bucks if you do it yourself.
IRISH-RACER-14
03-07-2011, 01:22 PM
i would if i was keeping the bike but im not going to. i bought it for 550euro. want to fix it and sell it for double that hopefully
mini racer #39
03-07-2011, 01:30 PM
Get the crank in top dead center...hold the rod..see if there is any top to bottom play...there will be side to side movement...if there is no top to bottom play then the crank is good...while holding the crank slowly rotate the motor and shift through the gears and make sure they go in and lock into gear...if all is good...reassemble and heat cycle...good luck
IRISH-RACER-14
03-07-2011, 01:33 PM
Originally posted by mini racer #39
Get the crank in top dead center...hold the rod..see if there is any top to bottom play...there will be side to side movement...if there is no top to bottom play then the crank is good...while holding the crank slowly rotate the motor and shift through the gears and make sure they go in and lock into gear...if all is good...reassemble and heat cycle...good luck

it does shift through the gears fine. i cant find any play in the rod besides the rod moving from side to side.


the guy said the bike was running last summer. it should start no problem if he was telling the truth with the newly refurb'd head and new piston,gaskets and spark plug?
mini racer #39
03-07-2011, 02:03 PM
Make sure you drain the old fuel...and check the reeds when reassembling...clean the carb while its easy to get too. and it should fire right up...
IRISH-RACER-14
03-07-2011, 02:18 PM
Originally posted by mini racer #39
Make sure you drain the old fuel...and check the reeds when reassembling...clean the carb while its easy to get too. and it should fire right up...

i drained the old fuel. reeds seem 2 be fine. ill change the gasket. this might sound stupid but how do i clean the carb?
Canadian144
03-07-2011, 02:47 PM
Disassemble the carb completely. Fill a bucket with carb cleaner (ammonia works well too), and put all the parts in there (with the exception of jets + gaskets/o-rings). I'd pick up a $30 carb rebuild kit as well.
IRISH-RACER-14
03-07-2011, 02:59 PM
Originally posted by Canadian144
Disassemble the carb completely. Fill a bucket with carb cleaner (ammonia works well too), and put all the parts in there (with the exception of jets + gaskets/o-rings). I'd pick up a $30 carb rebuild kit as well.


would that be wise?i could manage that but are they not set a certain way to make the bike run? and i went tampering with it wouldnt it be out of tune?
mini racer #39
03-07-2011, 03:17 PM
remove the 4 screws from the flote bowl remove bowl spray out the bowl with carb and choke cleaner spray out the jets reassemble and your good dont mess with the air and fuel screw all for about 2 bucks for the carb cleaner
IRISH-RACER-14
03-07-2011, 03:21 PM
ok thanks
Canadian144
03-07-2011, 03:54 PM
Originally posted by IRISH-RACER-14
would that be wise?i could manage that but are they not set a certain way to make the bike run? and i went tampering with it wouldnt it be out of tune?

Take note of the settings of the important screws. Do you have a service manual? They all show exactly how far in/out certain screws should be.
IRISH-RACER-14
03-07-2011, 04:16 PM
no im not sure if i will buy one or not. i guess i will have to
ZeroLogic
03-07-2011, 08:16 PM
As long as you don't mess with the air fuel screw and the jets you should be fine. You may even have to rejet the bike. It depends on a million things though.
IRISH-RACER-14
03-08-2011, 07:10 AM
so..if i have fuel,air,spark and compression then the bike should start correct?
ZeroLogic
03-08-2011, 11:59 AM
Well I'd hope so!:blah:

If you are worried about the jetting, you will figure out if its off the first time you hop on the bike. It shouldn't bog at all. There is a ton of articles on the web about how to jet two strokes. Your spark plug should be a brown/tan color.
buck440
03-09-2011, 01:53 PM
another thing you should know is that 2strokes take a while to warm up. every 2stroke i had/rode took a few minutes of idoling and about 3-5 minutes of "easy" riding before they showed the power. usually the bog bad if their not warmed up. this is my experience only.
ZeroLogic
03-09-2011, 02:09 PM
Originally posted by buck440
another thing you should know is that 2strokes take a while to warm up. every 2stroke i had/rode took a few minutes of idoling and about 3-5 minutes of "easy" riding before they showed the power. usually the bog bad if their not warmed up. this is my experience only.

Same over here. When the radiator is warm to touch you should be good to go.